Camera module

ABSTRACT

A camera module includes a lens, a first magnet and a second magnet mounted on a mobile body including the lens, a coil portion arranged near the first magnet and configured to move the first magnet in a first direction, and the magnetic sensor arranged near the second magnet and configured to detect the position of the second magnet in the first direction as a detection direction.

RELATED APPLICATION DATA

This application is a continuation application of U.S. patentapplication Ser. No. 16/681,898, filed Nov. 13, 2019, and is based onand claims priority to JP Application No. 2019-170466, filed Sep. 19,2019, and JP Application No. 2018-214181, filed Nov. 14, 2018, theentire contents of each of these applications are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates to camera modules.

BACKGROUND ART

Recent years have seen many terminals such as mobile phones equippedwith a mobile camera including a solid-state image sensor such as CCD orCMOS, where it is necessary for an optical system applied to the mobilecamera to have a position detecting mechanism capable of instantlyperforming highly accurate position detection. A position detectingdevice is known to meet such a need. In the device, the position of amagnet is detected by arranging two magnetic sensors side by side in adirection parallel to the direction of movement of a magnet (forexample, see JP3189365U).

SUMMARY

One of an object of the present disclosure is to provide a camera modulehighly flexible in the arrangement of magnets, coils, and magneticsensors and capable of detecting the positions of the magnets with highdetection accuracy.

To achieve the above object, a camera module according to one aspect ofthe present disclosure includes a lens, a first magnet and a secondmagnet mounted on a mobile body including the lens; a coil portionarranged near the first magnet and configured to move the first magnetin a first direction; and a magnetic sensor arranged near the secondmagnet and configured to detect a position of the second magnet in thefirst direction as a detection direction.

Additionally, a camera module according to another aspect of the presentdisclosure includes a lens; a magnet mounted on a mobile body includingthe lens; a coil portion including two coils arranged near the magnet,the coils being spaced apart from each other along one direction, beingarranged such that a winding axis of each of the coils faces a directionperpendicular to the one direction, and moving the magnet in thedirection perpendicular to the one direction; a magnetic sensorconfigured to detect a position of the magnet in the one direction; anda driver configured to drive the coil portion such that the two coilsrespectively generate magnetic fields having opposite polarities withrespect to the magnetic sensor.

According to the one aspect of the present disclosure, the position ofthe magnet can be detected with high detection accuracy regardless ofthe direction of movement of the magnet.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B are an external perspective view and a plan viewschematically illustrating one exemplary structure of a camera moduleaccording to a first embodiment of the present disclosure;

FIG. 2 is a cross-sectional view illustrating the one exemplarystructure of the camera module illustrated in FIG. 1;

FIG. 3 is a cross-sectional schematic view illustrating the arrangementof a magnet, a coil, and a magnetic sensor in the camera moduleaccording to the first embodiment of the present disclosure;

FIG. 4A is a graph illustrating a relationship between a distance of themagnet from a reference position and magnetic fluxes applied to twomagneto-electric transducers, and FIG. 4B is a graph illustrating arelationship between the distance of the magnet from the referenceposition and a sum of and a difference between the magnetic fluxesapplied to the two magneto-electric transducers;

FIG. 5 is a circuit block diagram for describing the camera moduleaccording to the first embodiment of the present disclosure;

FIG. 6 is a circuit block diagram for describing the camera moduleaccording to the first embodiment of the present disclosure in moredetail;

FIG. 7 is an external perspective view schematically illustrating onemodification of the camera module according to the first embodiment ofthe present disclosure;

FIG. 8 is an external perspective view schematically illustrating oneexemplary structure of a camera module according to a second embodimentof the present disclosure;

FIG. 9 is a cross-sectional schematic view illustrating the arrangementof a magnet, coils, and a magnetic sensor in the camera module accordingto the second embodiment of the present disclosure;

FIG. 10A is a graph illustrating a relationship between a distance ofthe magnet from a reference position and magnetic fluxes applied to twomagneto-electric transducers, and FIG. 10B is a graph illustrating arelationship between the distance of the magnet from the referenceposition and a sum of and a difference between the magnetic fluxesapplied to the two magneto-electric transducers;

FIG. 11 is a schematic view for describing an effect of the cameramodule according to the second embodiment of the present disclosure;

FIGS. 12A and 12B are circuit block diagrams for each describing acamera module according to another embodiment of the present disclosure;

FIGS. 13A and 13B are circuit block diagrams for each describing acamera module according to another embodiment of the present disclosure;and

FIGS. 14A and 14B are circuit block diagrams for each describing acamera module according to another embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

The following detailed description will describe many certain specificstructures to provide full understanding of embodiments of the presentdisclosure. It is however to be understood that such certain specificstructures are given for illustrative purposes only and otherembodiments are also possible. Additionally, the embodiments given belowdo not limit the invention according to the claims, and include all ofcombinations of characteristic structures described in the embodiments.

In the following description, the directions of “left and right” and “upand down” are defined merely for convenience of description and are notintended to limit the technical ideas of the present disclosure thereto.Therefore, for example, it is natural that when the drawing sheet isturned by 90 degrees, “left and right” and “up and down” should beexchanged one for the other, and that when the drawing sheet is turnedby 180 degrees, “left” should become “right” and “right” should become“left”.

Hereinafter, a first embodiment of the present disclosure will bedescribed with reference to the drawings. In the description of thedrawings below, the same portions are denoted by the same referencesigns. However, the drawings are schematic, and the relationship betweenthicknesses and planar dimensions, the ratios between thicknesses ofrespective layers, and the like are different from actual ones.

1. First Embodiment

A camera module according to the first embodiment of the presentdisclosure will be described with reference to FIG. 1A to FIG. 6. Acamera module 100 according to the present embodiment is included in acamera function-equipped electronic device. The camera function-equippedelectronic device in the present embodiment is, for example, a mobilephone device such as a smart phone, a digital camera, a digital movie,or the like.

[Structure of Camera Module]

FIG. 1A is a perspective view illustrating a schematic structure of thecamera module 100 included in a camera function-equipped electronicdevice, and FIG. 1B is a plan view of the camera module 100. FIG. 2 is across-sectional view illustrating a cross section taken along line II-IIof the camera module 100 illustrated in FIG. 1A. FIG. 1A and FIG. 2 omitillustration of a housing 4 mounted with a device 110 x including amagnetic sensor Sx and a device 110 y including a magnetic sensor Sy.The device 110 x includes the magnetic sensor Sx and a driver 120 xconfigured to control a current to be applied to a coil Cx.Additionally, the device 110 y includes the magnetic sensor Sy and adriver 120 y configured to control a current to be applied to a coil Cy.Details of the magnetic sensors Sx and Sy, the drivers 120 x and 120 y,and the housing 4 will be described later. In addition, for descriptiveconvenience, FIGS. 1A and 1B illustrate an XYZ orthogonal coordinatesystem set to correspond to the camera module 100.

As illustrated in FIGS. 1A and 1B, the camera module 100 includes a lensholder 21 that is a mobile body having a rectangular thin plate shapeand a lens 22 mounted in a through hole formed at the center of the lensholder 21. Additionally, under the lens 22, the camera module 100 mayinclude an image sensor (unillustrated), such as a CMOS image sensor,which is electrically coupled to a circuit board.

As illustrated in FIG. 1B, the lens holder 21 is provided on a holdermounting portion 41 of the housing 4 included in the camerafunction-equipped electronic device. The lens holder 21 is provided onthe holder mounting portion 41 so as to be movable with respect to thehousing 4. The camera module 100 also functions as a lens actuatormodule configured to move the lens 22 in a first direction or a seconddirection.

The camera module 100 includes a magnet M provided at least a part of aperiphery of the lens holder 21. The magnet M includes magnets Mx andMy. The magnet Mx and the magnet My are attached on side faces of thelens holder 21. The magnet My is arranged on the side face of the lensholder 21 orthogonal to the side face thereof where the magnet Mx isarranged.

As illustrated in FIG. 1B, the devices 110 x and 110 y are attached tothe housing 4.

The device 110 x is arranged facing the magnet My, and a coil Cyarranged facing the magnet My is provided around the device 110 x. Thedevice 110 y is arranged facing the magnet Mx, and around the device 110y is provided a coil Cx arranged facing the magnet Mx.

The coil Cx receives a current based on a drive signal Sdx output fromthe device 110 x on the basis of a position detection signal of themagnet My detected by the device 110 x. The coil Cy receives a currentbased on a drive signal Sdy output from the device 110 y on the basis ofa position detection signal of the magnet Mx detected by the device 110y.

As illustrated in FIGS. 1A and 1B, at a reference position (a designvalue) of the lens holder 21, a Z-axis direction of the XYZ orthogonalcoordinate system is set to correspond to an optical axis direction ofthe lens 22. Additionally, at the reference position of the lens holder21, an XY coordinate plane is set to correspond to a plane orthogonal tothe optical axis direction of the lens 22. In the present embodiment, adirection perpendicular to an optical axis of the lens 22 (an X-axisdirection in the present embodiment) is set to correspond to the firstdirection that is a direction in which the magnet Mx is moved by thecoil Cx. Additionally, a Y-axis direction perpendicular to the opticalaxis of the lens 22 and the first direction (the X-axis direction) isset to correspond to the second direction that is a direction in whichthe magnet My is moved by the coil Cy.

That is, the X-axis direction corresponds to a direction in which thecoil Cx and the magnet Mx are arranged facing each other. In otherwords, the coil Cx and the magnet Mx are arranged so that the directionof the winding axis of the Cx and the direction in which N- and S-polesof Mx are distributed are parallel to each other. Here the X-axisdirection corresponds to a direction in which long sides of the magnetMy extend. A direction from the coil Cx side to the magnet Mx side (thelens 22 side) is an X-axis positive direction. Furthermore, the Y-axisdirection is set to correspond to a direction in which the coil Cy andthe magnet My are arranged side by side. In other words, the Y-axisdirection corresponds to a direction in which long sides of the magnetMx extend. A direction from the magnet My side (the lens 22 side) to thecoil Cy side is a Y-axis positive direction.

[Operation of Camera Module]

In the camera module 100 of the present embodiment, the position of thelens 22 is determined by detecting the positions of the magnet Mx andthe magnet My attached to the lens holder 21. The position of the magnetMx is detected by the magnetic sensor Sy provided facing the magnet Mx.The position of the magnet My is detected by the magnetic sensor Sxprovided facing the magnet My. A method for detecting the positions ofthe magnet Mx and the magnet My will be described later.

In the camera module 100 of the present embodiment, drive current isapplied to the coil Cx arranged near the magnet Mx or the coil Cyarranged near the magnet My to move the magnet Mx or the magnet My. Forexample, applying drive current to the coil Cx generates a magneticfield around the coil Cx, and in accordance with the direction of themagnetic field, the magnet Mx can be moved in an X-axis positive ornegative direction. Similarly, applying drive current to the coil Cy canmove the magnet My in a Y-axis positive or negative direction.

Hereinafter, each component of the camera module 100 will be describedin detail.

(Magnetic Sensor)

The magnetic sensor Sx is a sensor arranged near the magnet My andconfigured to detect the position of the magnet My in the X-axisdirection as a detection direction. Additionally, the magnetic sensor Syis a sensor arranged near the magnet Mx and configured to detect theposition of the magnet Mx in the Y-axis direction as a detectiondirection. The magnetic sensors Sx and Sy are arranged such that thedirection of a magnetosensitive axis is perpendicular to each of theX-axis (the first direction) and the Y-axis (the second direction).

As illustrated in FIG. 1B, the magnetic sensor Sx and the magneticsensor Sy are mounted on the housing 4. Note that the magnetic sensor Sxand the magnetic sensor Sy may be mounted on the holder mounting portion41. The magnetic sensor Sy (one example of a first magnetic sensor) isarranged facing the magnet Mx. When the magnetic field changes due tomovement of the magnet Mx in the Y-axis direction, output voltage of themagnetic sensor Sy changes. The magnetic sensor Sx (one example of asecond magnetic sensor) is arranged facing the magnet My. When themagnetic field changes due to movement of the magnet My in the X-axisdirection, output voltage of the magnetic sensor Sx changes.

FIG. 3 is a cross-sectional view illustrating in detail a positionalrelationship between the magnet Mx, the coil portion Cx, and themagnetic sensor Sy. To facilitate understanding, FIG. 3 illustrates onlythe magnetic sensor Sy, and omits illustrations of the device 110 yincluding the magnetic sensor Sy and the driver 120 y included togetherwith the magnetic sensor Sy in the device 110 y.

As illustrated in FIG. 3, the magnetic sensor Sy includes twomagneto-electric transducers HEy1 and HEy2 arranged along the Y-axisdirection (one example of the second direction). In the magnetic sensorSy, the magneto-electric transducer HEy2 is arranged in a positivedirection of the Y-axis direction with respect to the magneto-electrictransducer HEy1. The magneto-electric transducers HEy1 and HEy2 arearranged such that when the magnet Mx moves in the Y-axis direction, thesign of a changed amount of a magnetic field detection signal Y1 outputby the magneto-electric transducer HEy1 is mutually opposite to the signof a changed amount of a magnetic field detection signal Y2 output bythe magneto-electric transducer HEy2.

Similarly, the magnetic sensor Sx includes two magneto-electrictransducers HEx1 and HEx2 (unillustrated) arranged along the X-axisdirection (one example of a first direction). In the magnetic sensor Sx,the magneto-electric transducer HEx2 is arranged in the X-axis positivedirection with respect to the magneto-electric transducer HEx1. Themagneto-electric transducers HEx1 and HEx2 are arranged such that thesign of an amount of change in a magnetic field detection signal X1output by the magneto-electric transducer HEx1 and the sign of an amountof change in a magnetic field detection signal X2 output by themagneto-electric transducer HEx2 when the magnet My is moved in the Xaxis direction are opposite to each other.

FIG. 4A is a graph illustrating a relationship between the position ofthe magnet Mx (a distance of the magnet Mx from a reference position)and outputs of the magneto-electric transducers HEy1 and HEy2 of themagnetic sensor Sy. In FIG. 4A, it is assumed that when the distance ofthe magnet Mx from the reference position is positive, the magnet Mx ispositioned in the Y-axis negative direction rather than the referenceposition.

Here, in FIG. 4A, the magnetic field detection signal Y1 output by themagneto-electric transducer HEy1 is indicated by a broken line, and themagnetic field detection signal Y2 output by the magneto-electrictransducer HEy2 is indicated by a dotted line. In FIG. 4B, a sum signal(Y1+Y2) of the magnetic field detection signal Y1 and the magnetic fielddetection signal Y2 is indicated by a dotted line, and a differencesignal (Y1−Y2) of the magnetic field detection signal Y1 and themagnetic field detection signal Y2 is indicated by a chain line. Asillustrated in FIG. 4B, the sum signal (Y1+Y2) is substantially constantregardless of the position of the magnet Mx. On the other hand, asillustrated in FIG. 4B, the difference signal (Y1−Y2) varies inaccordance with the position of the magnet Mx. Thus, by arranging themagneto-electric transducers HEy1 and HEy2 as in the present embodiment,a position detection signal indicating the position of the magnet Mx canbe obtained on the basis of a ratio of the difference signal (Y1−Y2) tothe sum signal (Y1+Y2) (i.e., (Y1−Y2)/(Y1+Y2)). Note that the positiondetection signal can also be obtained on the basis of a signalcorresponding to the ratio of the difference signal to the sum signal).For example, with the use of a ratio signal (Y1/Y2) of the magneticfield detection signal Y1 to the magnetic field detection signal Y2, theposition detection signal indicating the position of the magnet Mx canbe obtained on the basis of {(Y1/Y2)−1}/{(Y1/Y2)+1}.

In addition, the magnet My, the magnetic sensor Sx (the magneto-electrictransducers HEx1 and HEx2), and the coil portion Cy may be arrangedsimilarly to the magnet Mx, the magnetic sensor Sy (the magneto-electrictransducers HEy1 and HEy2), and the coil portion Cx in FIG. 3. In thiscase, a sum signal (X1+X2) of an output X1 of the magneto-electrictransducer HEx1 and an output X2 of the magneto-electric transducer HEx2is substantially constant regardless of the position of the magnet My.On the other hand, a difference signal (X1−X2) varies in accordance withthe position of the magnet My. Thus, by arranging the magneto-electrictransducers HEx1 and HEx2 as in the present embodiment, a positiondetection signal indicating the position of the magnet My can beobtained on the basis of a ratio of the difference signal (X1−X2) to thesum signal (X1+X2) (i.e., (X1−X2)/(X1+X2)).

Note that the position detection signal can also be obtained on thebasis of a signal corresponding to the ratio of the difference signal tothe sum signal). For example, with the use of a ratio signal (X1/X2) ofthe magnetic field detection signal X1 to the magnetic field detectionsignal X2, the position detection signal indicating the position of themagnet My can be obtained on the basis of {(X1/X2)−1}/{(X1/X2)+1}.

As the magnetic sensors Sx and Sy, for example, hall sensors can be usedthat use hall elements as the magneto-electric transducers HEx1, HEx2,HEy1, and HEy2. Alternatively, the magnetic sensors Sx and Sy may bemagnetic resistance (MR) sensors or the like using magnetic resistanceeffect elements (MR elements) as the magneto-electric transducers HEx1,HEx2, HEy1, and HEy2.

(Magnet)

The magnets Mx and My have a rectangular thin plate shape and are formedto have mutually substantially the same size. The magnets Mx and My aredipole permanent magnets having one N-pole and one S-pole. The magnetsMx and My are mounted on at least a part of the periphery of the lensholder 21. The magnet Mx is moved in the X-axis direction by the coilCx, and, in accordance with the movement of the magnet Mx, the lens 22is moved in the X-axis direction. Additionally, the magnet Mx moves inthe Y-axis direction when the magnet My is moved in the Y-axisdirection. The magnet My is moved in the Y-axis direction by the coilCy, and, in accordance with the movement of the magnet My, the lens 22is moved in the Y-axis direction. In addition, the magnet My moves inthe X-axis direction when the magnet Mx is moved in the X-axisdirection.

The magnet Mx is a dipole magnet whose N- and S-poles are distributed ina direction perpendicular to the direction in which the twomagneto-electric transducers HEy1 and HEy2 are arranged side by side inthe magnetic sensor Sy. Additionally, the magnet My is a dipole magnetwhose N- and S-poles are distributed in a direction perpendicular to thedirection in which the two magneto-electric transducers HEx1 and HEx2are arranged side by side in the magnetic sensor Sx. In other words, inFIGS. 1A and 1B, the magnet Mx is formed such that the S-pole isdistributed on the lens holder 21 side, and the N-pole is distributed onthe magnetic sensor Sy side. In addition, the magnet My is arranged suchthat the S-pole is distributed on the lens holder 21 side, and theN-pole is distributed on the magnetic sensor Sx side.

As illustrated in FIG. 3, the magnet Mx is arranged such that the samemagnetic pole (the N-pole in FIG. 3) faces each of the twomagneto-electric transducers HEy1 and HEy2 included in the magneticsensor Sy. Additionally, the magnet My is arranged such that the samemagnetic pole (the N-pole in FIG. 1) faces each of the twomagneto-electric transducers HEx1 and HEx2 included in the magneticsensor Sx.

(Coil)

As illustrated in FIG. 1B, the coils Cx and Cy are mounted on thehousing 4. The coil Cx is arranged near the magnet Mx. The coil Cxgenerates a magnetic field when current supplies thereto, and therebymoves the magnet Mx in the X-axis direction. The coil Cx moves themagnet Mx in the X-axis positive or negative direction in accordancewith the direction of a magnetic flux generated around the coil Cx. Thecoil Cy is arranged near the magnet My. The coil Cy generates a magneticfield when current supplies thereto, and thereby moves the magnet My inthe Y-axis direction. The coil Cy moves the magnet My in the Y-axispositive or negative direction in accordance with the direction of amagnetic flux generated around the coil Cy. In other words, the coil Cycan move the magnet My in the direction different from that of themagnet Mx.

The coil Cx is provided around the magnetic sensor Sy and arrangedfacing the magnet Mx. The coil Cx receives a current based on adetection signal (a signal indicating the position of the magnet My inthe X-axis direction) detected by the magnetic sensor Sx. In otherwords, a current for moving the magnet Mx to a target position in theX-axis direction on the basis of the position of the magnet My in theX-axis direction is supplied to the coil Cx.

The coil Cy is provided around the magnetic sensor Sx and arrangedfacing the magnet My. The coil Cy receives a current based on adetection signal (a signal indicating the position of the magnet Mx inthe Y-axis direction) detected by the magnetic sensor Sy. In otherwords, a current for moving the magnet My to a target position in theY-axis direction on the basis of the position of the magnet Mx in theY-axis direction is supplied to the coil Cy.

As a result, the coil Cx moves the magnet Mx in the X-axis direction onthe basis of the position of the magnet My in the X-axis directiondetected by the magnetic sensor Sx. In addition, the coil Cy moves themagnet My in the Y-axis direction on the basis of the position of themagnet Mx in the Y-axis direction detected by the magnetic sensor Sy.

(Device)

FIG. 5 is a block diagram illustrating one exemplary structure of thedevice 110 y including the magnetic sensor Sy and the driver 120 yconfigured to move the lens 22 to a target position in the Y-axisdirection. The device 110 y is formed by integrating the magnetic sensorSy with at least one of respective units (a position detection signalgenerator 130 y, a control signal generator 140 y, and a drive signalgenerator 150 y) forming the driver 120 y. The device 110 y may be, forexample, a monolithic IC in which the magnetic sensor Sy and the driver120 y are formed in or on a single substrate or a hybrid IC in which themagnetic sensor Sy and the driver 120 y are connected on a singlesubstrate. Alternatively, in the device 110 y, for example, the magneticsensor Sy and the driver 120 y may be integrated into a single package.One example of the device 110 y may be, for example, a hall IC or amagnetic resistance (MR) IC.

Hereinafter, operation of the driver 120 y will be described withreference to FIG. 5. The driver 120 y controls the coil Cy on the basisof the position of the magnet Mx in the Y-axis direction detected by themagnetic sensor Sy. The driver 120 y controls the coil Cy to move themagnet My, and thereby moves the lens 22 to a target position in theY-axis direction. Note that, to facilitate understanding of the controlby the driver 120 y, FIG. 5 illustrates the lens 22, the magnets Mx andMy, and the coil Cy other than the device 110 y including the driver 120y.

The driver 120 y includes the position detection signal generator 130 yconfigured to detect the position of the magnet Mx in the Y-axisdirection, the drive signal generator 150 y configured to drive the coilCy, and the control signal generator 140 y configured to control thedrive signal generator 150 y.

In addition, the camera module 100 includes the device 110 xunillustrated in FIG. 5. The device 110 x includes the magnetic sensorSx and the driver 120 x configured to move the lens 22 to a targetposition in the X-axis direction. The driver 120 x includes a positiondetection signal generator 130 x, a control signal generator 140 x, anda drive signal generator 150 x. The device 110 x is formed byintegrating the magnetic sensor Sx with at least one of the respectiveunits (the position detection signal generator 130 x, the control signalgenerator 140 x, and the drive signal generator 150 x) forming thedriver 120 x.

Hereinafter, the respective units of the driver 120 will be described indetail. In FIG. 6, the devices 110 x and 110 y, the drivers 120 x and120 y, and the position detection signal generators 130 x and 130 y willbe described as a device 110, a driver 120, and a position detectionsignal generator 130, without distinguishing each one from the other.Note that a description of the magnetic sensor Sy will be omitted.

(Position Detection Signal Generator)

The position detection signal generator 130 detects the position of themagnet Mx in the Y-axis direction on the basis of the magnetic fielddetection signals Y1 and Y2 respectively output from the twomagneto-electric transducers HEy1 and HEy2 of the magnetic sensor Sy.The position of the magnet Mx in the Y-axis direction is detected on thebasis of at least one of a sum signal of, a difference signal between,and a ratio signal between the magnetic field detection signals Y1 andY2 respectively output by the magneto-electric transducers HEy1 andHEy2.

As illustrated in FIG. 6, the position detection signal generator 130includes a calculator 132 and a detector 138. Additionally, asillustrated in FIG. 6, the magneto-electric transducers HEy1 and HEy2are connected to a power supply 80 to receive drive current or drivevoltage therefrom. The position detection signal generator 130 mayinclude an AD converter (unillustrated) configured to AD-convert themagnetic field detection signals Y1 and Y2. The AD converter isprovided, for example, in the calculator 132.

The calculator 132 includes an adder 136 a and a subtractor 136 b. Thecalculator 132 inputs the two magnetic field detection signals Y1 and Y2respectively output by the two magneto-electric transducers HEy1 andHEy2 to the adder 136 a, and outputs the sum signal (Y1+Y2) of themagnetic field detection signals Y1 and Y2 to the detector 138.Additionally, the calculator 132 inputs the magnetic field detectionsignals Y1 and Y2 to the subtractor 136 b, and outputs the differencesignal (Y1−Y2) between the magnetic field detection signals Y1 and Y2 tothe detector 138.

The detector 138 outputs, as the position detection signal Sp(Spy), forexample, the ratio {(Y1−Y2)/(Y1+Y2)} of the difference signal (Y1−Y2) tothe sum signal (Y1+Y2) to the control signal generator 140. As describedabove, the sum signal (Y1+Y2) indicates the substantially constant valueregardless of the position of the magnet Mx (see FIG. 4B). Thus, theposition detection signal Spy represented by {(Y1−Y2)/(Y1+Y2)} becomes asignal that varies in accordance with the position of the magnet Mx (arelative position with respect to the reference position of the magnetMx).

(Control Signal Generator)

The control signal generator 140 outputs a control signal Sc(Scy) tocontrol the drive signal generator 150. The control signal generator 140outputs the control signal Sc(Scy) on the basis of the positiondetection signal Sp(Spy) indicating the position of the magnet Mx in theY-axis direction input from the position detection signal generator 130and a target position signal Stp(Stpy) indicating a target position ofthe magnet My (the lens 22) in the Y-axis direction. The control signalgenerator 140 calculates an amount of movement of the magnet My to thetarget position in the Y-axis direction, for example, from a differencebetween the target position signal Stp and the position detection signalSp. The control signal generator 140 outputs the control signal Sccorresponding to the amount of the movement to the drive signalgenerator 150. Additionally, the control signal generator 140 may usePID control (proportional-integral-derivative controller) to output thecontrol signal Sc to the drive signal generator 150.

(Drive Signal Generator)

The drive signal generator 150 outputs the drive signal Sd(Sdy) to thecoil Cy on the basis of the control signal Sc(Scy) input from thecontrol signal generator 140. The drive signal Sd(Sdy) is a signal forapplying drive current to the coil Cy. The drive signal generator 150applies a predetermined drive current to the coil Cy on the basis of thedrive signal Sd(Sdy) to generate a magnetic field around the coil Cy andthereby move the magnet My by a predetermined amount in the Y-axisdirection. By doing this, the drive signal generator 150 moves the lens22 (the lens holder 21) mounted with the magnets Mx and My arranged awayfrom each other, in the Y-axis direction.

The description hereinabove has been given of the driver 120 driving thecoil Cy on the basis of the detection result of the magnetic sensor Sy.The same also applies to operation of the driver (unillustrated) drivingthe coil Cx on the basis of the position of the magnet My detected bythe magnetic sensor Sx.

[Modifications] (1) Modification 1

The camera module 100 according to the present embodiment may be formed,for example, as illustrated in FIG. 7. Specifically, the camera module100 may include, two coils Cy1 and Cy2, devices 110 x 1 and 110 x 2,magnetic sensors Sx1 and Sx2, and magnets My1 and My2 (the device 110 x2 and the magnetic sensor Sx2 are unillustrated), instead of each of thecoil Cy, the device 110 x, the magnetic sensor Sx, and the magnet My. Inthis case, the device 110 y outputs the drive signal Sdy to both of thecoils Cy1 and Cy2 from the driver 120 y in accordance with a result ofdetection of the position of the magnet Mx by the magnetic sensor Sy toapply current to the coils Cy1 and Cy2. Additionally, the devices 110 x1 and 110 x 2 output the drive signal Sdx to the coil Cx from each ofthe drivers 120 x 1 and 120 x 2 in accordance with results of detectionof the positions of the magnets My1 and My2 by the magnetic sensors Sx1and Sx2 to apply current to the coil Cx. In FIG. 7, outputs of the drivesignals Sdx and Sdy are schematically indicated by arrows.

Additionally, the camera module 100 may include two coils Cx1 and Cx2,devices 110 y 1 and 110 y 2, magnetic sensors Sy1 and Sy2, and magnetsMx1 and Mx2, instead of each of the coil Cx, the device 110 y, themagnetic sensor Sy, and the magnet Mx.

(2) Modification 2

In the camera module 100 according to the present embodiment, the firstdirection may be defined as a direction parallel to the optical axis ofthe lens 22 (i.e., Z-axis direction), and the second direction may bedefined as a direction perpendicular to the optical axis thereof (i.e.,X-axis direction or Y-axis direction). In this case, arranging a coilCz, a magnetic sensor Sz, and a magnet Mz under the lens 22 (the lensholder 21) can detect movement of the magnet Mz in the Z-axis direction.

(3) Modification 3

The camera module 100 according to the present embodiment serves todetect movement of the lens 22 in the X-axis direction or the Y-axisdirection and control the position of the lens 22 by driving the coilsCx and Cy in accordance with the result of the detection. However, theinvention is not limited thereto. For example, the camera module 100 mayfurther include the unillustrated coil Cz and magnet Mz that can movethe lens 22 in the Z-axis direction to serve to detect the movement ofthe lens 22 in the Z-axis direction and control the position of the lens22 in the Z-axis direction in accordance with the result of thedetection.

In this case, the magnet Mz is arranged facing the magnet Mx via thelens holder 21 therebetween. The magnet Mz is provided in the holdermounting portion 41 such that a distance between the magnet Mz and thedevice 110 z is maintained constant even when the lens holder 21 movesin the holder mounting portion 41 provided on the housing 4. The magnetMz is arranged outside the lens holder 21. The magnet Mz and the lensholder 21 are adapted to be movable independently of each other.

The device 110 z (unillustrated) configured to drive the coil Cz ismounted on the housing 4. Around the device 110 z is provided the coilCz arranged facing the magnet Mz. The coil Cz receives a current basedon a detection signal detected by the device 110 z.

As a result, the camera module 100 can perform not only blur correctionwithin an X-Y plane of the lens 22 but also blur correction in theZ-axis direction and focus correction of the lens 22.

(4) Modification 4

The camera module 100 according to the present embodiment may serve tocontrol the position of the lens 22 in the Z-axis direction, in additionto serving to control the position of the lens 22 in the X-axisdirection or the Y-axis direction, as with modification 3.

A camera module 100 of modification 4 includes, for example, threemagnets Mx, My, and Mz, three coils Cx, Cy, and Cz, and three devices110 x, 110 y, and 110 z. In the camera module 100 thus formed, themagnets Mx, My, and Mz are mounted on the lens holder 21, and the coilsCx, Cy, and Cz, respectively, are arranged near the magnets Mx, My, andMz. The device 110 x is arranged, for example, near the coil Cy or Cz,the device 110 y is arranged, for example, near the coil Cz or Cx, andthe device 110 z is arranged, for example, near the coil Cx or Cy.

The magnetic sensor Sx included in the driver 120 x detects the positionof the magnet My in the X-axis direction as a detection direction. Themagnetic sensor Sy included in the driver 120 y detects the position ofthe magnet Mz in the Y-axis direction as a detection direction. Themagnetic sensor Sz included in the driver 120 z detects the position ofthe magnet Mx in the Z-axis direction as a detection direction.

The coil Cx is driven by a drive signal from the driver 120 x to movethe magnet Mx in the X-axis direction as the first direction. The coilCy is driven by a drive signal from the driver 120 y to move the magnetMy in the Y-axis direction as the second direction. The coil Cz isdriven by a drive signal from the driver 120 z to move the magnet Mz inthe Z-axis direction as a third direction.

In other words, the camera module 100 of modification 4 includes a firstmagnet, a second magnet, and a third magnet that are mounted on a mobilebody. The coil portion includes a first coil portion configured to movethe first magnet in the first direction, a second coil portionconfigured to move the second magnet in the second direction differentfrom the first direction, and a third coil portion configured to movethe third magnet in the third direction different from both the firstand second directions. Additionally, the magnetic sensor includes afirst magnetic sensor configured to detect the position of the firstmagnet in the third direction as a detection direction, a secondmagnetic sensor configured to detect the position of the second magnetin the first direction as a detection direction, and a third magneticsensor configured to detect the position of the third magnet in thesecond direction as a detection direction.

In the camera module 100 thus formed, the magnetic sensors Sx, Sy, andSz are hardly influenced by magnetic fields leaked from the coils Cx,Cy, and Cz for respectively moving the lens 22 in the X, Y, and Z-axisdirections. Thus, regardless of the direction of movement of the lens22, the position of the lens 22 can be detected with higher detectionaccuracy.

(5) Modification 5

A camera module 100 of modification 5 includes, for example, two magnetsMx and Myz, three coils Cx, Cy, and Cz, and three devices 110 x, 110 y,and 110 z. The magnet Myz is a magnet arranged near both of the coils Cyand Cz and serving as both of the magnets My and Mz described inmodification 4. In this respect, it is different from the camera module100 of modification 4.

The coil Cx is arranged near the magnet Mx, and moves the magnet Mx inthe X-axis direction (one example of the first direction). The coil Cyis arranged near the magnet Myz, and moves the magnet Myz in the Y-axisdirection (one example of the second direction). The coil Cz is arrangednear the magnet Myz, and moves the magnet Myz in the Z-axis direction(one example of the third direction).

In other words, the camera module 100 of modification 5 includes a firstmagnet and a second magnet mounted on a mobile body. The coil portionincludes a first coil portion configured to move the first magnet in thefirst direction, a second coil portion configured to move the secondmagnet in the second direction, and a third coil portion configured tomove the second magnet in the third direction different from both of thefirst direction and the second direction. Additionally, the magneticsensor further includes a first magnetic sensor configured to detect theposition of the first magnet in the third direction as a detectiondirection.

[Effects of First Embodiment]

The camera module 100 according to the first embodiment has thefollowing effects: (1) The camera module is 100 highly flexible in thearrangement of magnets, coils, and magnetic sensors and capable ofdetecting the positions of the magnets with high detection accuracy.

2. Second Embodiment

A camera module according to a second embodiment of the presentdisclosure will be described using FIG. 8 to FIG. 11 while referring toFIG. 6. A camera module 200 according to the present embodiment candetect the position of a magnet with higher detection accuracy than thecamera module 100 according to the first embodiment.

In the camera module 100 according to the first embodiment, the magneticsensors Sy and Sx, respectively, are arranged at centers of the coil sCx and Cy. Thus, the magnetic sensors Sy and Sx detect not only magneticfields generated by the magnets Mx and My but also magnetic fieldsgenerated by current flow to the coils Cx and Cy. The camera module 200according to the second embodiment suppresses detection of magneticfields generated by the current flow to the coils Cx and Cy, and thusdetects the position of each of the magnets with higher detectionaccuracy.

[Structure of Camera Module]

As illustrated in FIG. 8, the camera module 200 includes a quadrupolemagnet M′ (Mx′ and My′), coils Cx1, Cx2, Cy1, and Cy2, and devices 110 xand 110 y. The device 110 x includes a magnetic sensor Sx and a driver120 x 1, and applies current to the coils Cx1 and Cx2 on the basis of adrive signal Sdx (indicated by arrows in FIG. 8) output from the driver120 x 1. The device 110 y includes a magnetic sensor Sy and a driver 120y, and applies current to the coils Cy1 and Cy2 on the basis of a drivesignal Sdy (indicated by arrows in FIG. 8) output from the driver 120 y.The device 110 y including the magnetic sensor Sy is arranged betweenthe two coils Cx1 and Cx2. Additionally, the device 110 x including themagnetic sensor Sx is arranged between the two coils Cy1 and Cy2. Thecamera module 200 also functions as a lens actuator module that movesthe lens 22 in the X-axis direction or the Y-axis direction.

As will be described later, the magnet Mx′ is arranged such thatdifferent magnetic poles thereof face each of the two magneto-electrictransducers HEy1 and HEy2 included in the magnetic sensor Sy. In otherwords, as illustrated in FIG. 8, the magnetic sensor Sy is arranged soas to face both of the S- and N-poles of the magnet Mx′. In addition,the magnet My′ is arranged such that different magnetic poles thereofface each of the two magneto-electric transducers HEx1 and HEx2 includedin the magnetic sensor Sx. In other words, as illustrated in FIG. 8, themagnetic sensor Sx is arranged so as to face both of the S- and N-polesof the magnet My′.

Hereinafter, each component of the camera module 200 will be describedin detail.

(Magnetic Sensor)

FIG. 9 is a cross-sectional view illustrating in detail a positionalrelationship between the magnet Mx′, the coils Cx1 and Cx2, and themagnetic sensor Sy. To facilitate understanding, FIG. 9 illustrates onlythe magnetic sensor Sy, and omits illustrations of the device 110 yincluding the magnetic sensor Sy and the driver 120 y included togetherwith the magnetic sensor Sy in the device 110 y.

As illustrated in FIG. 9, the magnetic sensor Sy includes twomagneto-electric transducers HEy1 and HEy2 arranged along the Y-axisdirection (one example of the second direction). Similarly, the magneticsensor Sx includes two magneto-electric transducers HEx1 and HEx2(unillustrated) arranged along the X-axis direction (one example of thefirst direction).

The magneto-electric transducers HEy1 and HEy2 are arranged such thatthe sign of an amount of change of a magnetic field detection signal Y1output by the magneto-electric transducer HEy1 and the sign of an amountof change of a magnetic field detection signal Y2 output by themagneto-electric transducer HEy2 when the magnet Mx′ is moved in theY-axis direction are the same to each other. In this respect, themagneto-electric transducers HEy1 and HEy2 are different from those ofthe first embodiment.

FIG. 10A is a graph illustrating a relationship between the position ofthe magnet Mx′ (a distance of the magnet Mx′ from a reference position)and magnetic fields applied to the magneto-electric transducers HEy1 andHEy2. In FIG. 10A, when the distance of the magnet Mx′ from thereference position is positive, the magnet Mx′ is positioned in theY-axis negative direction rather than the reference position.

Here, in FIG. 10A, a magnetic field detection signal Y1 output by themagneto-electric transducer HEy1 is indicated by a broken line, and amagnetic field detection signal Y2 output by the magneto-electrictransducer HEy2 is indicated by a dotted line. In FIG. 10B, a sum signal(Y1+Y2) of the magnetic field detection signal Y1 and the magnetic fielddetection signal Y2 is indicated by a dotted line, and a differencesignal (Y1−Y2) between the magnetic field detection signal Y1 and themagnetic field detection signal Y2 is indicated by a broken line. Asillustrated in FIG. 10B, the difference signal (Y1−Y2) is substantiallyconstant regardless of the position of the magnet Mx′. On the otherhand, as illustrated in FIG. 10B, the sum signal (Y1+Y2) varies inaccordance with the position of the magnet Mx′. Thus, by arranging themagneto-electric transducers HEy1 and HEy2 as in the present embodiment,a position detection signal can be obtained that indicates the positionof the magnet Mx′ on the basis of a ratio of the sum signal (Y1+Y2) tothe difference signal (Y1−Y2) (i.e., (Y1+Y2)/(Y1−Y2)).

Note that the position detection signal can also be obtained on thebasis of a signal corresponding to the ratio of the sum signal to thedifference signal. For example, with the use of a ratio signal (Y1/Y2)of the magnetic field detection signal Y1 to the magnetic fielddetection signal Y2, the position detection signal indicating theposition of the magnet Mx′ can be obtained on the basis of{(Y1/Y2)+1}/{(Y1/Y2)−1}.

Additionally, the magnet My′, the magnetic sensor Sx (themagneto-electric transducers HEx1 and HEx2), and the coils Cy1 and Cy2may be arranged similarly to the magnet Mx′, the magnetic sensor Sy (themagneto-electric transducers HEy1 and HEy2), and the coils Cx1 and Cx2in FIG. 9. In this case, a difference signal (X1−X2) between an outputX1 of the magneto-electric transducer HEx1 and an output X2 of themagneto-electric transducer HEx2 is substantially constant regardless ofthe position of the magnet My′. On the other hand, the sum signal(X1+X2) varies in accordance with the position of the magnet My′. Thus,by arranging the magneto-electric transducers HEx1 and HEx2 as in thepresent embodiment, a position detection signal can be obtained thatindicates the position of the magnet My′ on the basis of a ratio of thesum signal (X1+X2) to the difference signal (X1−X2) (i.e.,(X1+X2)/(X1−X2)).

Note that the position detection signal can also be obtained on thebasis of a signal corresponding to the ratio of the sum signal to thedifference signal. For example, with the use of a ratio signal (X1/X2)of the magnetic field detection signal X1 to the magnetic fielddetection signal X2, the position detection signal indicating theposition of the magnet My′ can be obtained on the basis of{(X1/X2)+1}/{(X1/X2)−1}.

(Magnet)

The magnets Mx′ and My′ are quadrupole permanent magnets having twoN-poles and two S-poles. The magnet Mx′ is a quadrupole permanent magnetin which the N-pole and the S-pole are distributed in a directionperpendicular to a direction in which the two magneto-electrictransducers HEy1 and HEy2 are arranged side by side in the magneticsensor Sy, and also the N-pole and the S-pole are distributed in adirection parallel to the direction in which the two magneto-electrictransducers HEy1 and HEy2 are arranged side by side. Additionally, Themagnet My′ is a quadrupole permanent magnet in which the N-pole and theS-pole are distributed in a direction perpendicular to a direction inwhich the two magneto-electric transducers HEx1 and HEx2 are arrangedside by side in the magnetic sensor Sx, and also the N-pole and theS-pole are distributed in a direction parallel to the direction in whichthe two magneto-electric transducers HEx1 and HEx2 are arranged side byside. Note that the magnets Mx′ and My′ are not limited to quadrupolemagnets and may be magnets having multipoles other than quadrupole.

As described above, the magnet Mx′ is arranged such that the differentmagnetic poles thereof face each of the two magneto-electric transducersHEy1 and HEy2 included in the magnetic sensor Sy. The magnet My′ isarranged such that the different magnetic poles thereof face each of thetwo magneto-electric transducers HEx1 and HEx2 included in the magneticsensor Sx.

(Coil)

The two coils Cx1 and Cx2 are arranged away from each other along theY-axis direction, and the two coils Cy1 and Cy2 are arranged away fromeach other along the X-axis direction. In other words, The coils arespaced apart from each other along one direction, being arranged suchthat a winding axis of each of the coils faces a direction perpendicularto the one direction. So they can move the magnet in the directionperpendicular to the one direction.

The coils Cx1 and Cx2 generate magnetic fields by supply of current, andmove the magnet Mx′ in the X-axis direction. The coils Cy1 and Cy2generate magnetic fields by supply of current, and move the magnet My′in the Y-axis direction. In other words, the coil Cy can move the magnetMy′ in the direction different from that of the magnet Mx′.

FIG. 11 is a cross-sectional view describing the magnetic fieldsgenerated by the coils Cx1 and Cx2 with respect to the magnetic sensorSy. To facilitate understanding, FIG. 11 illustrates only the magneticsensor Sy, and omits illustrations of the device 110 y and the driver120 y.

As illustrated in FIG. 11, the coils Cx1 and Cx2, respectively, areadapted to generate opposite polar magnetic fields with respect to themagnetic sensor Sy. The coils Cx1 and Cx2 preferably generate magneticfields having magnitudes as equal as possible with respect to themagnetic sensor Sy. As a result, in the position of the magnetic sensorSy, the magnetic field generated by current flow to the coil Cx1 and themagnetic field generated by current flow to the coil Cx2 are cancelled.This reduces influence of the magnetic fields from the coils Cx1 andCx2, so that the magnetic sensor Sy can output a signal indicating theposition of the magnet Mx′ with high accuracy.

To allow the coils Cx1 and Cx2 respectively to generate magnetic fieldshaving opposite polarities with respect to the magnetic sensor Sy, thecoils Cx1 and Cx2 are configured in any of the following manners: (i) Inthe coils Cx1 and Cx2, the winding directions of conductors are thesame, but current is applied in opposite directions (see FIG. 11); and(ii) In the coils Cx1 and Cx2, the winding directions of the conductorsare opposite, but current is applied in the same direction.

Similarly, the coils Cy1 and Cy2, respectively, are configured togenerate magnetic fields having opposite polarities with respect to themagnetic sensor Sx. Thus, in the position of the magnetic sensor Sx,influence of the magnetic fields from the coils Cy1 and Cy2 can bereduced.

To allow the coils Cy1 and Cy2 respectively to generate magnetic fieldshaving opposite polarities with respect to the magnetic sensor Sx, thecoils Cy1 and Cy2 are configured as in any of the (i) and (ii) describedabove.

(Position Detection Signal Generator)

The position detection signal generator 130 according to the secondembodiment will be described with reference to FIG. 6. As illustrated inFIG. 6, the position detection signal generator 130 includes thecalculator 132 and the detector 138. The position detection signalgenerator 130 according to the second embodiment outputs the positiondetection signal Sp(Spy) on the basis of the ratio of the sum signal(Y1+Y2) to the difference signal (Y1−Y2). In this respect, it isdifferent from the position detection signal generator 130 according tothe first embodiment.

The detector 138 outputs, for example, the ratio {(Y1+Y2)/(Y1−Y2)} ofthe sum signal (Y1+Y2) to the difference signal (Y1−Y2) as the positiondetection signal Spy to the control signal generator 140. As describedabove, in the present embodiment, the value of the difference signal(Y1−Y2) is substantially constant regardless of the position of themagnet Mx′ (see FIG. 10B). Thus, the position detection signal Spyrepresented by (Y1+Y2)/(Y1−Y2) is a signal that varies in accordancewith the position of the magnet Mx′ (a relative position with respect tothe reference position of the magnet Mx′).

[Effects of Second Embodiment]

The camera module 200 according to the second embodiment has, inaddition to the effect (1) of the first embodiment, the followingeffect: (2) The camera module 200 according to the second embodimentincludes the two adjacently arranged coils and the magnetic sensorarranged between the two coils and including the two magneto-electrictransducers; and additionally, in the camera module 200, the magnet isarranged such that the different magnetic poles thereof face each of thetwo magneto-electric transducers included in the magnetic sensor. Thetwo coils respectively are adapted to generate magnetic fields havingopposite polarities with respect to the magnetic sensor.

As a result, in the position of the magnetic sensor, the influence ofthe magnetic fields from the two coils can be reduced.

3. Other Embodiments

Hereinafter, other embodiments according to the present disclosure willbe described with reference to the drawings.

In the first and second embodiments, the position detection signalgenerator 130 has output the ratio between the sum signal (Y1+Y2) andthe difference signal (Y1−Y2) of the magnetic field detection signals Y1and Y2, as the position detection signal Sp. However, instead of this,the position detection signal generator 130 may perform calculations asbelow.

First Example of Other Embodiments

FIG. 12A is a block diagram illustrating a first example of otherembodiments. A position detection signal generator 230 illustrated inFIG. 12A is different from the position detection signal generator 130illustrated in FIG. 6 in that the former includes a calculator 232instead of the calculator 132 and a detector 238 instead of the detector138. The position detection signal generator 230 can be applied to thecamera module 100 of the first embodiment.

The position detection signal generator 230 includes the calculator 232and the detector 238.

The calculator 232 includes an amplifier 234 a connected to themagneto-electric transducer HEy1 and an amplifier 234 b connected to themagneto-electric transducer HEy2. In the amplifiers 234 a and 234 b, acoefficient (an amplification factor) is calculated such that the sumsignal (Y1+Y2) of an output signal of the amplifier 234 a and an outputsignal of the amplifier 234 b calculated by an adder 236 b is constant.The calculator 232 outputs a difference signal α(Y1−Y2) between anoutput signal αY1 of the amplifier 234 a and an output signal αY2 of theamplifier 234 b controlled by an amplification factor α, calculated by asubtractor 236 a, to the detector 238.

The detector 238 detects the position of the magnet Mx on the basis ofthe output (the difference signal α(Y1−Y2)) of the calculator 232.Additionally, the detector 238 outputs the position detection signal Spyof the magnet Mx as the position detection signal Spy to the controlsignal generator 140. The position detection signal Spy indicates, forexample, a relative position from the reference position of the magnetMx in the Y-axis direction.

The position detection signal generator 230 illustrated in FIG. 12A isreplaced by a position detection signal generator 330 when applied tothe camera module 200 of the second embodiment.

The position detection signal generator 330 illustrated in FIG. 12Bincludes a calculator 332 instead of the calculator 132 and a detector338 instead of the detector 138. In this respect, the position detectionsignal generator 330 is different from the position detection signalgenerator 130 illustrated in FIG. 6.

The position detection signal generator 330 includes the calculator 332and the detector 338.

The calculator 332 includes an amplifier 334 a connected to themagneto-electric transducer HEy1 and an amplifier 334 b connected to themagneto-electric transducer HEy2. In the amplifiers 334 a and 334 b, acoefficient (an amplification factor) is calculated such that thedifference signal (Y1−Y2) between an output signal of the amplifier 334a and an output signal of the amplifier 334 b calculated by a subtractor336 b is constant. The calculator 332 outputs a sum signal α(Y1+Y2) ofthe output signal αY1 of the amplifier 334 a and the output signal αY2of the amplifier 334 b controlled by the amplification factor α,calculated by an adder 336 a, to the detector 338.

The detector 338 detects the position of the magnet Mx on the basis ofthe output (the sum signal α(Y1+Y2)) of the calculator 332.Additionally, the detector 338 outputs the position detection signal Spyof the magnet Mx as the position detection signal Spy to the controlsignal generator 140. The position detection signal Spy indicates, forexample, a relative position from the reference position of the magnetMx in the Y-axis direction.

Second Example of Other Embodiments

FIG. 13A is a block diagram illustrating a second example of otherembodiments. A position detection signal generator 430 illustrated inFIG. 13A is different from the position detection signal generator 130illustrated in FIG. 6 in that the former includes a calculator 432instead of the calculator 132 and a detector 438 instead of the detector138. The position detection signal generator 430 can be applied to thecamera module 100 of the first embodiment.

The position detection signal generator 430 includes the calculator 432and the detector 438.

The calculator 432 inputs the sum signal (Y1+Y2) of the output Y1 fromthe magneto-electric transducer HEy1 and the output Y2 from themagneto-electric transducer HEy2 calculated by an adder 436 b to anamplification factor calculator 435. The amplification factor calculator435 calculates a coefficient (an amplification factor) such that the sumsignal (Y1+Y2) is constant. An amplifier 434 calculates to multiply thedifference signal (Y1−Y2) between the output Y1 from themagneto-electric transducer HEy1 and the output Y2 from themagneto-electric transducer HEy2 calculated by a subtractor 436 a by anamplification factor β input from the amplification factor calculator435. The calculator 432 outputs a product β(Y1−Y2) of the differencesignal (Y1−Y2) by the amplification factor β as a calculation result tothe detector 438.

On the basis of the output of the calculator 432, the detector 438detects the position of the magnet Mx. Additionally, the detector 438outputs the position detection signal Spy of the magnet Mx to thecontrol signal generator 140. The position detection signal Spyindicates, for example, a relative position from the reference positionof the magnet Mx in the Y-axis direction.

The position detection signal generator 430 illustrated in FIG. 13A isreplaced by a position detection signal generator 530 illustrated inFIG. 13B when applied to the camera module 200 of the second embodiment.

The position detection signal generator 530 includes a calculator 532and a detector 538.

The calculator 532 inputs the difference signal (Y1−Y2) between theoutput Y1 from the magneto-electric transducer HEy1 and the output Y2from the magneto-electric transducer HEy2 calculated by a subtractor 536b to an amplification factor calculator 535. The amplification factorcalculator 535 calculates a coefficient (an amplification factor) suchthat the difference signal (Y1−Y2) is constant. An amplifier 534calculates to multiply the sum signal (Y1+Y2) of the output Y1 from themagneto-electric transducer HEy1 and the output Y2 from themagneto-electric transducer HEy2 calculated by an adder 536 a by theamplification factor β input from the amplification factor calculator535. The calculator 532 outputs a product β(Y1+Y2) of the sum signal(Y1+Y2) by the amplification factor β as a calculation result to thedetector 538.

On the basis of the output of the calculator 532, the detector 538detects the position of the magnet Mx. Additionally, the detector 538outputs the position detection signal Spy of the magnet Mx to thecontrol signal generator 140. The position detection signal Spyindicates, for example, a relative position from the reference positionof the magnet Mx in the Y-axis direction.

Third Example of Other Embodiments

FIG. 14A is a block diagram illustrating a third example of otherembodiments. A position detection signal generator 630 illustrated inFIG. 14A is different from the position detection signal generator 130illustrated in FIG. 6 in that the former includes a calculator 632instead of the calculator 132 and a detector 638 instead of the detector138. The position detection signal generator 630 can be applied to thecamera module 100 of the first embodiment.

The position detection signal generator 630 includes the calculator 632and the detector 638.

The calculator 632 calculates the output values of the magnetic sensorSy such that the sum signal (Y1+Y2) of the output Y1 from themagneto-electric transducer HEy1 and the output Y2 from themagneto-electric transducer HEy2 calculated by an adder 636 b isconstant. On the basis of a result of the calculation, the calculator632 controls the power supply 80 to drive the magnetic sensor Sy suchthat the sum signal (Y1+Y2) is constant.

The position detection signal generator 630 may include a magneticsensor drive controller (unillustrated) configured to control drivevoltage or drive current of the magnetic sensor Sy such that the sumsignal (Y1+Y2) of the magnetic sensor Sy is constant. The magneticsensor drive controller controls the power supply 80 to control thedrive voltage or drive current of the magnetic sensor Sy.

The detector 638 detects the position of the magnet Mx on the basis ofthe difference signal (Y1−Y2) calculated by a subtractor 636 a on thebasis of the corrected output values Y1 and Y2 from the magnetic sensorSy. Additionally, the detector 638 outputs the position detection signalSpy of the magnet Mx to the control signal generator 140. The positiondetection signal Spy indicates, for example, a relative position fromthe reference position of the magnet Mx in the Y-axis direction.

The position detection signal generator 630 illustrated in FIG. 14A isreplaced by a position detection signal generator 730 illustrated inFIG. 14B when applied to the camera module 200 of the second embodiment.

The position detection signal generator 730 includes a calculator 732and a detector 738.

The calculator 732 calculates the output values of the magnetic sensorSy such that the difference signal (Y1−Y2) between the output Y1 fromthe magneto-electric transducer HEy1 and the output Y2 from themagneto-electric transducer HEy2 calculated by a subtractor 736 b isconstant. On the basis of a result of the calculation, the calculator732 controls the power supply 80 to drive the magnetic sensor Sy suchthat the difference signal (Y1−Y2) is constant.

The position detection signal generator 730 may control input values tothe magnetic sensor Sy such that the difference signal (Y1−Y2) of themagnetic sensor Sy is constant. In this case, the position detectionsignal generator 730 may include a magnetic sensor drive controller(unillustrated) configured to control drive voltage or drive current ofthe magnetic sensor Sy. The magnetic sensor drive controller controlsthe power supply 80 to control the drive voltage or drive current of themagnetic sensor Sy.

The detector 738 detects the position of the magnet Mx on the basis ofthe sum signal (Y1+Y2) calculated by an adder 736 a on the basis of thecorrected output values Y1 and Y2 from the magnetic sensor Sy.Additionally, the detector 738 outputs the position detection signal Spyof the magnet Mx to the control signal generator 140. The positiondetection signal Spy indicates, for example, a relative position fromthe reference position of the magnet Mx in the Y-axis direction.

Each of the structures of the position detection signal generators inthe first to third examples of the other embodiments has been describedhereinabove. However, it is obvious that each example may be performedin the same manner as above by using the outputs X1 and X2 from themagnetic sensor Sx.

While some embodiments of the present disclosure have been describedhereinabove, the embodiments depicted above exemplify devices andmethods for embodying the technological idea of the present disclosure,in which the technological idea of the present disclosure does notspecify the materials, shapes, structures, arrangement, and the like ofcomponents. Various modifications can be made to the technological ideaof the present disclosure without departing from the technological scopeprescribed by the claims.

REFERENCE SIGNS LIST

-   -   4: Housing    -   21: Lens holder    -   22: Lens    -   41: Holder mounting portion    -   80: Power supply    -   100, 200: Camera module    -   110, 110 x, 110 y: Device    -   120, 120 x, 120 y: Driver    -   130: Position detection signal generator    -   140: Control signal generator    -   150: Drive signal generator    -   Sx, Sy: Magnetic sensor    -   HEx1, HEx2, HEy1, HEy2: Magneto-electric transducer    -   Mx, My, Mx′, My′: Magnet    -   Cx, Cx1, Cx2, Cy, Cy1, Cy2: Coil

1. A camera module, comprising: a magnet mounted on a mobile body; and acoil portion including two coils arranged facing the magnet, the coilsbeing spaced apart from each other along one direction, being arrangedsuch that a winding axis of each of the coils faces a directionperpendicular to the one direction, and moving the magnet in thedirection perpendicular to the one direction, wherein the two coils arearranged facing each of magnetic poles of the magnet magnetized todifferent polarities.
 2. The camera module according to claim 1, whereinthe magnet is a magnet in which the N-pole and the S-pole aredistributed in a direction parallel to the direction in which the twocoils are arranged side by side.
 3. The camera module according to claim2, wherein one of the two coils is arranged facing the N-pole and notfacing the S-pole, and wherein the other of the two coils is arrangedfacing the S-pole and not facing the N-pole.
 4. The camera moduleaccording to claim 1, wherein both of the two coils of the coil portionare arranged facing the magnet on the same side face with respect to themagnet.
 5. The camera module according to claim 1, comprising a magneticsensor arranged between the two coils and configured to detect aposition of the magnet in the one direction.
 6. The camera moduleaccording to claim 5, wherein the magnetic sensor is arranged betweenthe two coils when viewed from a direction perpendicular to the onedirection.
 7. The camera module according to claim 6, wherein themagnetic sensor includes two magneto-electric transducers arranged alongthe one direction, and wherein the camera module further comprises aposition detection signal generator configured to output a positiondetection signal indicating the position of the magnet on a basis of atleast one of a sum signal of, a difference signal between, and a ratiosignal between two magnetic field direction signals respectively outputby the two magneto-electric transducers.
 8. The camera module accordingto claim 7, wherein the magnet is arranged such that different magneticpoles face each of the two magneto-electric transducers included in themagnetic sensor, and wherein the position detection signal generatoroutputs the position detection signal on a basis of a ratio of the sumsignal to the difference signal.
 9. The camera module according to claim5, comprising a driver configured to drive the coil portion such thatthe two coils respectively generate magnetic fields having oppositepolarities with respect to the magnetic sensor.
 10. The camera moduleaccording to claim 9, wherein in the two coils, winding directions ofconductors are the same to each other, and wherein the driver appliescurrent to the two coils in opposite directions to each other.
 11. Thecamera module according to claim 9, wherein in the two coils, windingdirections of conductors are opposite to each other, and wherein thedriver applies current to the two coils in the same direction to eachother.
 12. The camera module according to claim 1, wherein the mobilebody include the lens.
 13. The camera module according to claim 1,comprising a drive control device, the drive control device including: aplurality of magneto-electric transducers arranged facing each ofmagnetic poles magnetized to different polarities of a first magnetarranged on a first side face of the mobile body and detects a magneticfield generated by the first magnet; an AD converter configured toAD-convert each of magnetic field detection signals respectively outputby the plurality of magneto-electric transducers; a calculator includingan adder configured to outputs a sum signal of the plurality of themagnetic field detection signals and a subtractor configured to outputsa difference signal between the plurality of the magnetic fielddetection signals; a control signal generator configured to outputcontrol signals for moving a second magnet arranged on a second sideface intersecting with the first side face of the mobile body on thebasis of a position detection signal indicating a position of the magnetin a one direction and a target position signal indicating a targetposition of the magnet in the one direction, the position detectionsignal is calculated based on the sum signal and the difference signal;and a drive signal generator configured to output drive signals to acoil arranged on facing a second magnet on the basis of the controlsignals.
 14. A drive control device, comprising: a plurality ofmagneto-electric transducers arranged facing each of magnetic polesmagnetized to different polarities of a first magnet arranged on a firstside face of a mobile body and detects a magnetic field generated by thefirst magnet; an AD converter configured to AD-convert each of magneticfield detection signals respectively output by the plurality ofmagneto-electric transducers; a calculator including an adder configuredto outputs a sum signal of the plurality of the magnetic field detectionsignals and a subtractor configured to outputs a difference signalbetween the plurality of the magnetic field detection signals; a controlsignal generator configured to output control signals for moving asecond magnet arranged on a second side face intersecting with the firstside face of the mobile body on the basis of a position detection signalindicating a position of the magnet in a one direction and a targetposition signal indicating a target position of the magnet in the onedirection, the position detection signal is calculated based on the sumsignal and the difference signal; and a drive signal generatorconfigured to output drive signals to a coil portion arranged on facinga second magnet on the basis of the control signals.
 15. The drivecontrol device according to claim 14, wherein the magneto-electrictransducers are hall sensors.
 16. The drive control device according toclaim 14, wherein the drive signal generator electrically couples to thecoil portion including a first coil and a second coil arranged facingthe second magnet and configured to generate the magnetic fields havingopposite polarities, and wherein the drive signal generator outputs thecontrol signals to the first coil and the second coil.
 17. The drivecontrol device according to claim 14, wherein the calculator includes anamplification factor calculator configured to calculate a coefficientsuch that the sum signal is constant, and wherein the calculator outputsa product of the difference signal by the coefficient input from theamplification factor calculator.
 18. The drive control device accordingto claim 14, wherein the calculator includes an amplification factorcalculator configured to calculate a coefficient such that thedifference signal is constant, and wherein the calculator outputs aproduct of the sum signal by the coefficient input from theamplification factor calculator.
 19. The drive control device accordingto claim 14, wherein the drive signal generator outputs the drive signalto the coil portion arranged facing the second magnet arranged on thesecond side face.
 20. The drive control device according to claim 14,wherein the drive control device is arranged between a third coil and afourth coil, the third coil and the fourth coil are arranged facing thefirst magnet.